Signal modifier valve



March 8, 1960 A. J. SAGADY SIGNAL MODIFIER VALVE 2 Sheets-Sheet 1 Filed Jan. 29, 1958 INVENTOR.

x I? iii ATTORNEY March 8, 1960 J, s D 2,927,568

SIGNAL MODIFIER VALVE Filed Jan. 29, 1958 2 Sheets-Sheet 2 INVENTOR.

United States Patent SIGNAL MODIFER VALVE Alexander J. Sagady, Centerline, Micln, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Application January 29, 1958, Serial No. 711,994

7 Claims. (Cl. 123-119) The present invention relates to a fuel injection system of the mass air flow type as generally shown in copend ing application Serial No. 608,853, Dolza, filed September 10, 1956, now Patent No. 2,843,098, granted July 15, 1958. In particular, the present device represents an improvement over the earlier D0121 system in providing a novel cold enrichment mechanism. In the earlier Dolza system a solenoid mechanism was provided which retained the fuel metering valve in a maximum flow position for a timed interval to obtain an enriched starting mixture. Such control results in a step type enrichment which approximates but does not reflect the actual needs of the engine. The timed type of enrichment does not take into account engine temperature which results in over-enrichment when starting a warm engine.

In the present system a device is provided whereby a modulated enrichment of the system is achieved and which enrichment is accurately determined by the needs of the engine during warm-up. In the present device the modulated enrichment is achieved by providing a metering signal modifying valve which is controlled by temperature and air flow in such a way as to vary the metering vacuum signal in inverse proportion to such temperature and air flow.

I In the present invention a contoured diffuser element is provided in the induction passage to provide an annular venturi which in general is the same construction as in the earlier filed Dolza application. However, in the present invention the contoured diffuser element is somewhat larger than was previously the case making a smaller annular venturi more restrictive of air flow insurfng a strong fuel metering signal under low air flow conditions. In addition, a high air flow capacity passage is formed through the contoured diffuser element and a valve disposed therein to control the flow therethrough. The valve is adapted to restrict the opening of the high capacity passage to limit the inducted air flow to that amount which may pass through the annular venturi. In this way it is possible to maintain a strong metering signal under low air flow conditions or under conditions in which fuel enrichment is desired.

On the other hand, when the engine has warmed sufficiently and a high inducted air flow capacity is desirable, the valve controlling fiow through the high capacity passage may be opened to provide the requisite air flow consistent with engine demand. Thus the aforenoted valve becomes a signal modifier valve adapted to control the fuel metering signal in accordance with any engine operating control force desired. In the present invention it is proposed to control the signal modifier valve by a temperature responsive element which will therefore function to provide suitable fuel enrichment when the engine is cold and which will permit maximum air fiow through the induction passage after the engine has warmed sufficiently.

The details as well as other objects and advantages of the present invention are set forth in the description which follows.

In the drawings:

Figure 1 is a partially sectioned view of a fuel injection system embodying the subject invention;

. Figure 2 is an enlarged sectional view of the venturi and signal modifier valve; and

Figure 3 is an elevational view showing the signal modifier valve actuating mechanism in greater detail.

Except as will hereinafter be specifically pointed out, the present fuel injection system functions in the same manner as in the aforenoted copending Dolza application. Briefly, the fuel injection system includes an intake casing 10 having an air induction passage 12 formed therethrough. The induction passage 12 includes a contoured diffuser element 13 disposed therein which coacts with the casing 10 to define an annular venturi 14. A throttle valve 16 is also disposed in the induction passage 12 posteriorly to venturi 14. The induction passage communicates with an air manifold or plenum chamber 18 from which the air is supplied to the individual cylinders of the engine through intake passages 20. Fuel under pressure is supplied from a source 21 to a valve member indicated generally at 22 where the fuel is metered through the action of a diaphragm controlled linkage mechanism 24. The metered fuel from valve 22 is supplied to conduits 26 which communicate with the individual cylinder intake passages 20 and each of which conduits terminates in a nozzle member 28. In this way the fuel and air are adapted to be mixed just prior to their induction into the engine cylinders 30.

Metering valve control mechanism 24 includes a diaphragm 32 having a vacuum chamber 34 which communicates with venturi 14 through a conduit 36 and an annular venturi chamber 38. The diaphragm 32 also includes another chamber 41 which is vented to the atmosphere through a conduit 43 within the induction passage 12 anteriorly of the venturi 14.

As already noted, in the earlier Dolza application a solenoid was provided for retaining the metering valve 22 in a maximum fuel output position to provide cold starting enrichment. The solenoid type enrichment control represents an approximation of engine needs and which cold starting and running enrichment control is considerably refined by the mechanism now to be described.

The theory of the present device has been to provide a mechanism whereby the metering control force acting on diaphragm 32 is reinforced or supplemented in inverse proportion to engine air flow and temperature. In this way when the engine is coldest a strong metering signal will be generated and will retain the metering valve 22 in its maximum fuel output position. The reinforcing of the metering signal will progressively diminish or be modulated as the engine warms and becomes cap:.ble of running on a leaner fuel-air mixture.

While in general the contoured diffuser element 13 is the same as that provided in the aforenoted Dolza appli-' cation, it is specifically diiferent and represents an improvement thereover permitting a significant foreshortening of the induction passage 12 in addition to improved and simplified fuel enrichment operation. Contoured diffuser element 13 may be supported within the induction passage 12 by a plurality of radial spiders or flanges, not shown, in a way permitting axial flow of the air entering induction passage 12. Further, it is to be noted that the annular cross sectional area betw:en the induction pas sage and the contoured diffuser element is reduced particularly at the venturi throat. This smaller cross sectional area venturi is possible for reasons to be subsequently discussed. However, by being able to provide a smaller venturi throat it is also possible to reduce the length of the venturi while maintaining venturi efliciency."

The reduction in venturi size permits a reduction in the Patented Mar. 1960 length ofthe inductionpassage and an appreciable saving iii-space.

In the earlier Dolza construction it was necessary to use a larger venturi cross sectional area in order to insure sufficient air flow through the induction passage under high air flow conditions. The larger venturi construction inevitably creates the problem of securing a sufficiently strong metering signal under low air flow conditions. This is avoided in the present device by providing a straight sided passage 4% through contoured diffuser element 13 and which passage has a considerably greater air flow capacity than does the annular venturi 14. Further, by providing a valve 42 in the passage 40, it is possible to restrict or eliminate flow through the passage whereby air flow will be limited to the annular venturi passage which, due to its smaller cross sectional area or throat than previous constructions, will insure a strong metering signal under low air flow conditions. On the other hand, when the engine is in condition to utilize and requires greater quantities of air, the signal modifier valve 42 may be opened.

it is apparent that the control of the signal modifier valve 42, may be made responsive to a number of engine operating conditions. However, in the present device it is desired to control the valve 42 in accordance with engine temperature and air flow. When the engine is cold the valve will be closed insuring a high air fiow through the annular venturi providing an abnormally high metering signal whereby fuel enrichment will take place until such time as the engine warms sufiiciently to open the signal modifier valve whereby air will begin to flow through the passage 40.

Before describing the mechanism for operating the signal modifier valve 42, it is to be noted that the valve has been relieved at 44 to permit overlapping of the signal modifier valve and'the throttle valve 16. in'this way the throttle valve will nest within the relieved por- 2,927,5es a i p times. Further, such venturi is uniquely combined with a high volume passage in parallel therewith and which passage may be controlled to provide fuel enrichment under cold starting and running conditions.

During cold starting and cold running operation engine friction is naturally higher than during warm engine operation. For this reason it is normal practice to provide means for supplying a greater charge to the engine when the latter is cold than when it is warm. For this purpose it is customary to provide a fast idle cam mem.-

with which an adjusta'ble screw member 62mounted on tion of the signal modifier valve making possible a further reduction in the length of the induction passage.

To maintain the modifier valve 42 in a closed position and to open the same as the engine warms, a temperature responsive mechanism indicated generally at 46 is provided. The temperature responsive mechanism includes a bimetallic coil element 48 adapted to be anchored at one end to the induction passage casing and fixed at its other end to the modifier valve shaft 58 through appropriate levers 52 and 54 and link 55. Thermostatic coil 48 is so arranged that the force with which it retains the valve 42 in a closed position varies inversely with temperature.

It may also be desirable to make modifier valve 42 responsive to engine load which may be manifested by manifold vacuum. To this end, temperature responsive mechanism 46 may include a vacuum piston device of the type shown and described in copending application Serial No. 658,091 Dolza et al., filed May 9, 1957, for modifying valve actuation.

Since it is desirable to make the modifier valve 42 unbalanced whereby it will tend to open in response to air flow, it is apparent that the actuation of the valve is normally responsive to three forces, namely, engine temperature, load and air flow. 7

Thus, with the engine cold, the signal modifier valve will be maintained in a closed position insuring high velocity-low volume air flow through the annular venturi 14. This creates a reinforced or higher fuel metering signal which is transmitted to metering control diaphragm 32 providing the requisite fuel enrichment. Thereafter, as engine temperature and air flow increase, valve 42 will be progressively opened until such time as full air flow through the contoured difiuser element is possi- .bl

Thus a mass air flow responsive fuel metering system isprovided in which-a high. velocity-low volume venturi isi tilized for insuring a, strong metering signal at all a lever 64 fixed to the throttle shaft 66 can coact toregulate the quantity of air which flows past the throttle 16 during idling conditions. Cam 58 is articulated through link 68 to lever 52. Thus as engine temperature increases, the fast idle cam is adapted to be rotated in .a clockwise direction, as viewed in Figure 3, causing the screw 62 to progressively engage lower steps of the cam and reduce the engine idling speed.

It is apparent that various structural modifications may be made in the present device within the scope of the invention set forth in the appended claims.

I claim:

1. A fuel injection system for an internal combustion engine comprising an air induction passage, an annular venturi means disposed in said induction passage, 21 throttle valve in said induction passage posteriorly of said venturi means, a plurality of intake passages communicating the induction passage with the individual cylinders of said engine, a source of fuel under pressure, conduit means for communicating said fuel source with the intake passages, a metering valve intermediate said fuel source and said conduit means, diaphragm means for actuating said metering valve, an annular chamber formed in said induction passage and communicating with said venturi means, a conduit communicating said chamber with said diaphragm means for increasing the flow through said metering valve with an increase in air flow through said venturi, air flow responsive valve means disposed in said induction passage of said venturi means, and a temperature responsive memberjoperatively cou nected to said air flow responsive valve means for urging said valve means toward an air flow restricting position to increase the vacuum force in said induction passage chamber whereby said metering valve will insure an enriched fuel-air mixture when the engine is cold, said temperature responsive member being adapted to open said air flow valve as the engine warms.

2. A fuel injection system for an internal combustion engine comprising an air induction passage, an annular venturi means disposed in said induction passage, a throttle valve in said induction passage posteriorly of said venturi means, a plurality of intake passages communieating the induction passage with the individual cylinders of said engine, a source of fuel under pressure, conduit means for communicating said fuel source with the intake passages, 21 metering valve intermediate said fuel source and said conduit means, diaphragm means for actuating said metering valve, an annular chamber formed in said induction passage and communicating with said venturi means, a conduit communicating said chamber with said diaphragm means for increasing the flow through said metering valve with an increase in air flow through said venturi, air fiow responsive valve means disposed in said induction passage of said venturi means, and a temperature responsive member operatively connected to said air flow responsive valve means for urging said valve means toward an air flow restricting position to increase the vacuum force in said induction passage chamber whereby said metering valve will insure an enriched fuel-air mixture when the engine is cold, said temperature. responsive member being adapted toopen said air flow valve as the engine warms, andaengine load responsive means for modifying the operation of the temperature responsive member.

3. A fuel injection system for an internal combustion engine comprising an air induction passage, intake passages communicating the induction passage with the individual cylinders of the engine, a source of fluid under pressure, conduit means communicating said fuel source with the individual intake passages, valve means for metering the quantity of fuel flow through said conduit means, diaphragm means for controlling the actuation of said valve, a venturi in said induction passage, a conduit communicating with said venturi and said diaphragm means whereby said latter means is actuated to increase the output of said metering valve in proportion to the mass of air flow through said venturi, a throttle valve disposed in said induction passage posteriorly of said venturi, and valve means disposed in said induction passage anteriorly of said throttle valve for modifying the diaphragm metering control force in accordancewith certain engine operating conditions.

4. A fuel injection system for an internal combustion engine comprising an air induction passage, intake passages communicating the induction passage with the individual cylinders of the engine, a source of fluid under pressure, conduit means communicating said fuel source with the individual intake passages, valve means for metering the quantity of fuel flow through said conduit means, diaphragm means for controlling the actuation of said valve, an annular venturi in said induction passage, a conduit communicating with said venturi and said diaphragm means whereby said latter means is actuated to increase the output of said metering valve in proportion to the mass of air flow through said venturi, a throttle valve disposed in said induction passage posteriorly of said venturi, an air passage in parallel with the annular venturi, and valve means disposed in said latter passage for modifying the diaphragm metering control force in accordance with certain engine operating conditions.

5. A fuel injection system for an internal combustion engine comprising an air induction passage, intake passages communicating the induction passage with the individual cylinders of the engine, a source of fluid under pressure, conduit means communicating said fuel source with the individual intake passages, valve means for me tering the quantity of fuel flow through said conduit means, diaphragm means for controlling the actuation of said valve, a venturi in said induction passage, a conduit communicating with said venturi and said diaphragm means whereby said latter means is actuated to increase the output of said metering valve in proportion to the mass of air flow through said venturi, a throttle valve disposed in said induction passage posteriorly of said venturi, and valve means adapted to restrict a portion of the air flow through said induction passage for modifying the diaphragm metering control force in accordance with certain engine operating conditions, a cam for limiting the idle position of the throttle valve and means connecting said valve means and cam whereby the position of said cam is determined by the position of said valve means.

6. A fuel injection system as set forth in claim 4 in which said venturi and parallel related air passage are concentrically arranged.

7. A fuelinjection system for an internal combustion engine comprising an air induction passage, intake passages communicating the induction passage with the individual cylinders of the engine, the source of fluid under pressure, conduit means communicating said fuel source with the individual intake passages, valve means for metering the quantity of fuel flow through said conduit means, diaphragm means for controlling the actuation of said valve, a contoured diffuser element disposed within said induction passage and cooperating therewith to define an annular venturi, an annular chamber formed within the induction passage casing adjacent the venturi throat and communicating at one end therewith, a conduit communicating said chamber and said diaphragm means whereby the latter means is actuated to increase the output of said metering valve in proportion to the mass of air flow through said venturi, a throttle valve disposed in said induction passage posteriorly of said venturi, a passage formed longitudinally through said contoured diffuser element to provide an air flow passage having a greater capacity than the annular venturi passage, valve means disposed in said contoured difiuser element, and engine temperature responsive means connected to said valve and adapted to maintain said valve in a closed position when the engine is cold whereby air flow is limited to the venturi passage insuring a sufliciently strong metering signal to provide fuel enrichment until such time as the engine temperature warms sufliciently to progressively open said valve permitting air to flow through the contoured difliuser element.

References Cited in the file of this patent UNITED STATES PATENTS 2,673,556 Reggio Mar. 30, 1954 

